The extraction of crude oil produces a high quantity of water, which can be as free fluid or as an emulsion in crude oil. If during the extraction and transport stages, theses fluids suffer high shear stress, stable water in oil emulsions are obtained. This can happen even in ducts, such as pumping zones, storage tanks, treatment installations and refineries. Water in crude oil emulsions consists of water droplets dispersed in a homogeneous phase of crude oil.1,2 Stability of water in crude oil depends strongly on the adsorption-desorption kinetic of natural surfactants (mainly asphaltenes) and the rheological properties of interfacial film. This film is formed as a consequence of the supramolecular interactions of emulsifiers with molecules of high boiling point, such as asphaltenes and resins, which decrease the interfacial tension and provoke the water droplet dispersion. Asphaltenes are molecules that have several condensed aromatic rings with different aliphatic and naphthenic substituents, which are able to stack, coordinating simultaneously with water droplets and avoid coalescence.
Nowadays, there are physical and chemical methods that are employed individually or sequentially to break the emulsion of water dispersed in crude oil. The physical methods include an electric field and mechanic effect device. These methods can be combined with heat, in order to increase the frequency and collision forces between the dispersed water droplets.1,2,3,4 
Regarding the chemical treatment, breaking the water in crude oil emulsion requires the addition of a demulsifier compound, which is a surfactant that reduces and breaks the interfacial film between components, increasing the coalescence of water droplets. The election of the most convenient demulsifier depends on several factors: concentration, characteristic of crude oil, time of emulsion mixed and optimal residence time.
Demulsifiers employed in the crude oil industry are commercial formulations that have several chemical product families (ethylene and propylene oxide copolymers, alkoxylates resins of alkoxyphenol formaldehyde, alkoxylated amines, alkoxylated resins of alkoxyphenol formaldehyde, alkoxylated amines, alkoxylated epoxy resins, etc) dissolved in one or several solvents (toluene, xylene, alcohols of short chain, naphtha, etc.).5 
Pluronic® and Tetronic® are commercial formulations that are applied as demulsifier and emulsion water in crude oil breakers. The first one is a triblock copolymer of polyoxyethylene-polyoxypropylene-polyoxyethylene (POE-POP-POE) that use ethyleneglycol as an initiator. The second one also is a triblock copolymer of polyoxypropylene-polyoxyethylene-polyoxypropylene (POP-POE-POP) which uses ethylenediamine as an initiator.6,7 
U.S. Pat. Nos. 2,425,845 and 3,334,038 disclose the production process of copolymers with POE-POP-POE structure and the usage of following glycols as initiators of polymerization: ethyleneglycol, 1,2-propyleneglycol, 1,3-propyleneglycol, buthyleneglycol, diethyleneglycol, dipropyleneglycol, triethyleneglycol, tripropyleneglycol and others aliphatic glycols.8,9 
U.S. Pat. No. 3,835,060 discloses a process to break an emulsion using a formulation of ether-alkyl-polyglycol sulphates and block copolymers of polyoxyethylene-polyoxypropylene. The chemical structure of alkylpolyglycol ethers used in this process are shown in formula 1, where R is the alkyl group (n=1-10 and M is an alkaline metal, alkaline earth metal or quaternary nitrogen atom. Emulsion breaking occurs after 120 minutes, when the mixture is added at concentration of 20 to 140 ppm; although the crude oil type is not specified, a maximum separation of water 35% was described.10

U.S. Pat. No. 5,445,765 discloses demulsifiers of alkoxylated polyethylenimines with propylene oxide and ethylene oxide, which can be employed successfully in a temperature range between 10 and 130° C. These dehydrating agents were used in crude oil of Oriental Affric, giving a separation 47% in three hours. However, crude oil composition is not mentioned in the patent.11 
U.S. Pat. No. 5,609,794 discloses polyalkylglycol and ethylene oxide, which is esterified with an anhydride in order to obtain a diester. This compound was made to react with a vinyl monomer to synthesize several esters. Formulations are applied in a concentration range of 10 to 1500 ppm and in a range of 7 and 80° C. Products employed as dehydrating agents of crude oil (characterization is not mentioned) and other refinery products (turbosine, gasoline, lubricants, etc.). The patent discloses a water separation of 40% obtained in a few minutes.12 
U.S. Pat. No. 6,294,093 discloses a formulation of demulsifiers composed of dicarbamates and polyalkoxylate alkylphenol resin. The formulations are composed for water and soluble organic compound, and are applied to water in crude oil emulsion in concentrations between 50 to 1000 ppm; the characteristics of crude oil are not mentioned.13 
U.S. Patent Publication No. 2004/0266973 discloses an alkylphenol arylaldehyde alkoxylated polymer able to separate water-oil emulsion, including crude oil and other refinery fluids. This is applied as a prepared formulation in several organic solvents and naphtha, concentrations of 1 to 3000 ppm, but the main characteristics of crude oil are not mentioned.14 
International Publication No. WO 2007/115980 discloses an ortho-ester alkoxylated provoking the separation of water in an emulsion. The general structure of the ortho-ester is shown in formula 2, where R1 is H or a hydrocarbon chain, R2, R3 and R4 are alkyloxy and/or ethyloxy groups of C3-C4 carbon atoms. The described products in this publication were evaluated in North Sea and Orient Medium crude oils. It was determinate a separation between 30 and 100% for these products.15

From the economical and operational point of view, it is very important to separate the water from crude oil emulsions and, simultaneously, to remove the inorganic salts dissolved in the aqueous phase, diminishing, by this way, the corrosion in petroleum industry and the catalyst poisoning during the refining stage. Furthermore, the removal of water improves quality storage, exploitation and use of crude oil.
Considering the great importance of these technical necessities, formulations of bifunctionalized block copolymers with secondary amines of low polydispersity have been produced, that are more efficient than the commercial formulations in the dehydrating of heavy crude oil. These copolymers are disclosed in Mexican Patent Mx/a/2008/015756 registration number and Mexican Patent No. 301344, issued Jun. 27, 2012.
With the same target to resolve these technical necessities, new formulations of bifunctionalized block copolymers with tertiary amines of low polydispersity were obtained, which also resulted in very efficient break up of water in heavy crude oil emulsion. These copolymers are disclosed in Mexican patent Mx/a/2013/002359.
Under both types of formulations, bifunctionalized block copolymers with secondary amines and bifunctionalized block copolymers with tertiary amines, show high efficiency of the commercial formulations in the breakup of water in heavy crude oil emulsion. It was evident of the need for synthesizing at industrial scale both types of copolymers for their future application in some oil fields in Mexico.
However, the synthesis described in both patents was done at laboratory scale (50-100 g), which was too expensive for its application at industrial level.
The synthesis begins when ethylene glycol reacts with potash (KOH) in methanol as a solvent to obtain the salt named potassium ethyleneglycolate (EGP), which was first made to react with propylene oxide (OP) and after with ethylene oxide (OE) to obtain the triblock copolymer ethylene polyethylene oxide-polypropylene oxide-polyethylene oxide (POEw-POPy-POEw).
Afterwards, the POEw-POPy-POEw copolymer, that has an end hydroxyl group, is submitted to reaction in dichloromethane with tosyl chloride (TsCl) to obtain the tosilated triblock copolymer (Ts-POEw-POPy-POEw-Ts). This reaction was carried out to convert the hydroxyl group as good leaving group and that is susceptible to nucleophilic substitution. Until this synthesis stage there is similarity to the Mx/a/2008/015756 and Mx/a/2013/002359 patent applications.
The difference occurs when the Ts-POEw-POPy-POEw-Ts copolymer reacts with different secondary amines to obtain the bifunctionalized copolymers disclosed in the Mx/a/2008/015756 patent application.16,17 On the other hand, when the copolymer reacts with tertiary amines, the copolymers described in the Mx/a/2013/002359 patent application are synthesized.
Bifunctionalized copolymers with amines owe the efficiency to the following factors: inclusion of the appropriate functional group, correct proportion of the triblocks, low monodispersity and ideal molecular weight; this last was demonstrated recently by dissipative particle dynamics study.18 